Part:BBa_K5310020
T1 hairpin arm
INTRODUCTION
The use of miRNAs as biomarkers and therapeutic molecules is seeing rapid advancements in the last decade. As a continuation of this, it is possible to combine the two functions with a mechanism that detects certain signature miRNAs of the disease and releases miRs with restorative effects based on a technique called Hybridization Chain Reaction.
MECHANISM OVERVIEW
The mechanism consists of two types of nucleic acid hairpins, a set of HCR hairpins and a T-shaped one. The first HCR hairpin is activated by an initiator molecule triggering a series of unbindings and hybridizations resulting in the release of two therapeutic molecules. The T hairpin recognizes the biomarker miRNAs and undergoes gradual unbinding of its arms upon which the initiator is released. It operates as a safety measure to make sure the HCR procedure mentioned above occurs in the right cells or tissue, where the therapeutic miRNAs should execute their function.
Different conditions are characterized by a different miRNA expression profile. It is therefore necessary to carefully select those according to which the hairpins would be designed. In the case of Multiple Sclerosis with the purpose of remyelination, one should examine which miRNAs are overexpressed in patient oligodendroglia (myelin generating cells) and which have the ability to enhance their desired function, while taking hairpin structure requirements into account. Upon literature review, discussions with neurologists and in silico testing, it was concluded that miR-125a-3p and miR-146a-5p are the biomarkers the T hairpin would be based on, whereas miR-219-5p and miR-338-3p are the remyelinating miRNAs released by HCR.
PART FUNCTION
This part was designed as an integral component of the T hairpin (which is comprised of three arms;T1,T2,T3). It includes the T1a module that is complementary to the Y3 arm, the Y1b module that is complementary to the Y2 arm and a toehold sequence at the end of T1a that is complementary to miR-125a-3p. When the T hairpin is delivered to patient OPCs and Ols (the target cells with high levels of biomarker miRs), miR-125a-3p binds to the hairpin sequence and causes the T1 arm to unbind from the structure, becoming an inactive molecule and leaving an exposed strand in the T2 arm that sets the rest of the mechanism forward.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
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